LECTURE 4
EXCAVATING & LIFTING
Sung-Woo MOON, Ph.D, P.E
September 14 , 2018
Nazarbayev University
Department of Civil Engineering
Lecture 04
ECE 404: Construction Technologies & Processes 2
•An excavator : a power-driven digging machine
•The major types of excavators
–Hydraulic excavators
–Members of the cable-operated crane-shovel family
•e.g., shovels, draglines, hoes, and clamshells
–Dozers, loaders, and scrapers (can also serve as
excavators)
EXCAVATING & LIFTING
EQUIPMENT
Lecture 04
ECE 404: Construction Technologies & Processes 3
•First excavator
–Steam-powered, single-bucket
excavator (William Otis, 1836)
–Used in railroad construction
•Cable-operated crane-shovel family
–Shovel
–Backhoe
–Dragline
–Clamshell
–Mobile crane
–Pile driver
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 4
Shovel Backhoe Dragline
Clamshell Mobile crane Pile driver
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 5
•Hydraulic excavators
–Largely replace the cable-operated crane-shovel family
–Functionally be similar with front shovel and backhoe
–Many attachments available
•E. g. clamshells, augers, compactors, and hammers
•Advantage of hydraulic excavators over cable-operated
machines
–Faster cycle time
–Higher bucket penetrating force
–More precise digging
–Easier operator control
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 6
•Hydraulic excavators &
attachments
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 7
•Hydraulic telescoping-boom mobile cranes
•The major remaining cable-operated machines based on
the original crane-shovel
–Dragline
–Mobile lattice-boom crane
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 8
•Three major assemblies for excavators and
crane-shovels
–Carrier or mounting
•Crawler
•Truck
•Wheel mountings
–Revolving superstructure containing the power and
control units (also called the revolving deck or
turntable)
–Front-end assembly
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 9
•Hydraulic excavators
Carrier (mounting)
Revolving superstructure
Front-end assembly
EXCAVATORS & CRANE SHOVELS
Three major assemblies
Lecture 04
ECE 404: Construction Technologies & Processes 10
•The crawler mounting
–Excellent on-site mobility – will go anywhere
–Low ground pressure –good for low trafficability soils
–Widely used for drainage and trenching work as well as for
rock excavation
•Wheel mountings
–Greater mobility between job sites –faster
–Required better surfaces –less stable
–Use a single operator’s station to control both the carrier and
the excavating mechanism
–Highway travel capability: 48 km/h (30 mi/h)
EXCAVATORS & CRANE SHOVELS
Lecture 04
ECE 404: Construction Technologies & Processes 11
•Truck mountings
–Greater mobility between job sites –faster
–Required better surfaces –less stable
–Use a modified truck chassis as a carrier and thus
have separate stations for operating the carrier and
the revolving superstructure
–Highway travel capability: 50 mi/h (80 km/h)
EXCAVATORS & CRANE SHOVELS
•Production of excavator
𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 𝑉𝑜𝑙𝑢𝑚𝑒 𝑝𝑒𝑟 𝑐𝑦𝑐𝑙𝑒 × 𝐶𝑦𝑐𝑙𝑒𝑠 𝑝𝑒𝑟 ℎ𝑜𝑢𝑟
𝐶𝑜𝑠𝑡 𝑝𝑒𝑟 𝑢𝑛𝑖𝑡 𝑜𝑓 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝑐𝑜𝑠𝑡 𝑝𝑒𝑟 ℎ𝑜𝑢𝑟
EXCAVATOR PRODUCTION
